Kidneys have outer layers {cortex, kidney}.
Kidneys have inner layers {medulla, kidney}.
In kidney cortex, blood capillaries {glomerulus, kidney} {glomeruli, kidney} surround nephrons.
In kidney cortex, glomeruli surround small tubules {nephron}.
In kidney cortex, sacs {Bowman's capsule} {Bowman capsule} surround capillaries. Urea, creatinine, uric acid, ammonia, and ions diffuse under pressure into Bowman's capsule.
Below Bowman's capsule, tubules loop {proximal convoluted tubule}, and active transport returns glucose, amino acids, salts, and water by reabsorption to blood.
Proximal convoluted tubules dip down into kidney medulla and then back up to kidney cortex {Henle loop} {loop of Henle}.
In kidney cortex, looped regions {distal convoluted tubule} secrete selected substances back into urine from blood for augmentation.
Distal convoluted tubules go into kidney medulla {collecting tubule}, where countercurrent processes regulate water concentration, as low-concentration fluid passes by high-concentration fluid in opposite direction and diffusion balances water in blood and urine.
Collecting tubules can become funnel-shaped chambers {renal pelvis}.
4-Zoology-Organ-Excretion-Kidney
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Date Modified: 2022.0225